Remove outdated resources (#4295)
Remove outdated resources (#4295)

Removed links to Youtube videos that are no longer available and updated a link to a tutorial that has moved.
kgeorgy/django-rest-framework,linovia/django-rest-framework,dmwyatt/django-rest-framework,davesque/django-rest-framework,johnraz/django-rest-framework,atombrella/django-rest-framework,johnraz/django-rest-framework,tomchristie/django-rest-framework,jpadilla/django-rest-framework,dmwyatt/django-rest-framework,kgeorgy/django-rest-framework,johnraz/django-rest-framework,uploadcare/django-rest-framework,ossanna16/django-rest-framework,edx/django-rest-framework,edx/django-rest-framework,kgeorgy/django-rest-framework,dmwyatt/django-rest-framework,tomchristie/django-rest-framework,linovia/django-rest-framework,davesque/django-rest-framework,ossanna16/django-rest-framework,uploadcare/django-rest-framework,jpadilla/django-rest-framework,atombrella/django-rest-framework,atombrella/django-rest-framework,uploadcare/django-rest-framework,edx/django-rest-framework,davesque/django-rest-framework,tomchristie/django-rest-framework,linovia/django-rest-framework,ossanna16/django-rest-framework,jpadilla/django-rest-framework